A controller that did a bunch of the shortcut actions would be fine for WoW.
But the real problem with doing a WoW CP would be the fact that you still need a keyboard to type messages to others in the game

A CP designed around a keyboard with a bunch of buttons and lights around it might look kinda funky. But yeah, a separate custom controller like a belkin nostromo kinda thing might help in WoW.
BTW, I love my belkin nostromo n52 for games, AND for applications too. Its not just for games. I love how you can program each key with scripts or with toggle functions, or with always on functions, or with mouse buttons, etc. Its so freaking versatile, and its nice to have seperate profiles for various games too. So for instance, one application I have when I do document merges, it insists on putting the last piece first. So I'd have to click my mouse button 100 times to get it back to bottom of list (don't ask, it doesn't have mouse drag). With the nostromo, I just program a key to do 100 mouse clicks and bang every time I hit it it does it

One game I played had dual pistols that were semi automatic. I got tired of hitting the mouse button 30 times each time I wanted to drain the pistols. So I setup a button on the nostromo to rapid fire them as long as I held down a button on it. I tweaked the delay between each simulated mouse press so it was down to the minimum required. Once I used that my pistols were firing as fast as a machine gun

For the lego indiana/batman group of games I setup a key that I can hit that continually auto fires or auto whacks. I don't use it very often (feels almost like cheating lol) but sometimes there are crowds of annoying enemies in my way and I've beaten the level 5 times already without doing the trick and I just need to beat it again to get 100% completion so I'll use it.
And its definately not cheaply made, I've been pounding on mine for years and it still works just like it did when it was new. It also reduces strain on the wrist/hand as well. I typically play with the controller sitting on my lap, although it has a rubber bottom that would let you play on a desk without it slipping.
http://catalog.belkin.com/IWCatProductPage.process?Product_Id=164714